The present invention relates to information processing systems and data communications systems, especially data communications interfaces of information processing systems.
The present invention is directed to an improved data processing system. More specifically, the present invention provides a system and method for providing multiple virtual host channel adapters using virtual switches within a physical channel adapter of a system area network.
In a system area network (“SAN”), such as a network in accordance with InfiniBand architecture (“IBA”), the hardware provides a message passing mechanism that can be used for input/output devices (“I/O”) and interprocess communications (“IPC”) between general computing nodes. Processes executing on devices access SAN message passing hardware by posting send/receive messages to send/receive work queues on a SAN host channel adapter (“HCA”). These processes are also referred to as “consumers.”
The send/receive work queues (“WQ”) are assigned to a consumer as a queue pair (“QP”). Consumers retrieve the results of these messages from a completion queue (“CQ”) through SAN send and receive work completion (“WC”) queues. The source channel adapter takes care of segmenting outbound messages and sending them to the destination. The destination channel adapter takes care of reassembling inbound messages and placing them in the memory space designated by the destination's consumer.
Two channel adapter types are present in nodes of the SAN fabric, a host channel adapter (“HCA”) and a target channel adapter (“TCA”). The host channel adapter is used by general purpose computing nodes to access the SAN fabric. Consumers use SAN verbs to access host channel adapter functions. Target channel adapters (TCA) are used by nodes that are the subject of messages sent from host channel adapters. The target channel adapters serve a similar function as that of the host channel adapters in providing the target node an access point to the SAN fabric.
The processing power and connectivity of medium and large scale computing systems, frequently referred to as servers or “mainframes”, have recently experienced rapid increases. These improvements have been accompanied by improvements in the flexibility with which they can be programmed and used. Often it is beneficial to logically partition individual components and resources within such computing systems so as to support a plurality of operating system environments. Such logical partitioning allows each operating system, and applications operating within that operating system environment, to view the resources of the system as being dedicated to that operating system environment even though, in actuality, the resources are shared by a plurality of operating system environments. Such logical partitioning allows a system to support multiple different environments and thus, increases the versatility of the system while reducing the cost of maintaining the different environments by sharing of resources.
Building, operating and maintaining a large number of individual small scale computing systems, e.g., personal computers or “PCs” or even doing the same for mid-size computing systems involve significant costs in administering changes and updates to the hardware, operating systems, as well as administering changes and updates to applications which they support. These factors make the total cost of owning and operating such small- and mid-scale computing systems significant.
As the scale of server computer systems increases, it is desirable to further increase the flexibility of uses to which such systems can be put, by enabling support for a larger number of logical partitions on a single processor node of a SAN. A larger number of logical partitions will support a corresponding larger number of operating system images. Each operating system image, in turn, can support an environment tailored to the needs of a particular customer who uses the logical partition. Therefore, by providing facilities for creating and maintaining larger numbers of logical partitions, greater flexibility is provided such that the server computer can be shared among a great number of customers or customer uses when desired. Enabling larger numbers of logical partitions to be supported by one server helps assure that the processor resources and input/output resources of a server are best utilized.